Chair arm



FIG. 1 is a side elevational view of a chair arm showing my new design, the opposite side being a mirror image thereof; FIG. 2 is a three quarter side elevational view of a chair arm showing my new design, the opposite side being a mirror image thereof; FIG. 3 is a three quarter front elevational view of a chair arm showing my new design, the opposite side being a mirror image thereof; FIG. 4 is top view of a chair arm showing my new design; FIG. 5 is a bottom view; FIG. 6 is a front elevational view of a chair arm showing my new design; and, FIG. 7 is a rear elevational view of a chair arm showing my new design. The broken line showing of a chair is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a chair arm, as shown and described. 